I have a soldering problem with a header SMT straight single row of 8 pins. It's a samtec #TSM-108-03-T-SV-P (P&P). The first problem I have is an allignement one. I do not use alignement pin for now but I expect to use it. Concerning soldering, I apply solder paste with a stencil of 0.006'' and I also have 0402 components on this PCB. I'm sure of one thing, my printing process and the reflow are not the source of the problem. The printer is a full automatic printer so my solder paste is perfectly centered on pads. I've placed thermocouple directly on the pin and on pads also to be sure I respect the profil of solder paste. Everything is good with a peak of 220 deg. The thing I'm not sure is ... with the size of the SMT pad on PCB and a thickness of only 0.006'' of solder paste do you think that increasing the pad size could be a good solution.

Dear Frank, could it be that your component legs are coated with a leadfree finish? This can have an inpact on soldering when your temp.peak in only 220�C and the melting point of pure Tin is 237�C. Best regards, Daniel